This invention relates to improved adapters for attaching a radiator cooling fan of an internal combustion engine to the water pump of the engine.
In performing repair work on the cooling system of an internal combustion engine, it frequently becomes necessary or desirable to insert an adapter unit between the water pump of the engine and the radiator cooling fan driven thereby, in order to assure proper positioning of the fan relative to the radiator. The use of such an adapter may be required, for example, when an automatic temperature responsive fan driving clutch unit has become inoperative and is being removed without replacement. There have in the past been devised various different types of adapters for this purpose, but each has had distinct disadvantages in use. One prior adapter currently on the market consists of an annular body having a rear flange containing radial slits through which bolts extend to secure the body to a water pump, and having a forward flange containing radial slits for attaching a fan thereto, with an annular groove or space being provided between the two flanges. In order to connect the rear flange to the water pump, it is necessary in such a device to insert a wrench radially inwardly into the annular groove in the adapter body, to engage and turn the heads of screws which project rearwardly into a portion of the water pump. However, the depth of the annular groove has been limited by the necessity for provision of a central portion of the body for securing the front and rear flanges together, and because of this depth limitation it has been difficult in many situations to properly engage the head of the bolt with an inserted tool. Consequently, attachment of the adapter to a water pump has required very careful manipulation of a tool in a space which is really not large enough for proper reception of the tool, and has therefore entailed expenditure of an excessive amount of time in the installing process. Further, the central portion of the adapter, between the front and rear flanges, has necessarily been relatively weak, and on occasion has broken under the forces encountered in operation of the mechanism. In addition, though the rear flange in that prior arrangement has been effectively located relative to the water pump by reception of a pilot projection on the pump into a pilot recess in the rear portion of the adapter, the fan itself has not been effectively centered relative to the front flange to which it is connected, and if slightly off-center may produce a great deal of vibration and noise when the fan is turning.
Another type of adapter now on the market includes a body which is reversible so that either of two opposite ends of the body may be connected to the water pump, while the other end is connectable to a fan, with an opening extending through the body for reception of a pilot projection on the water pump in either of the two positions, and with a first set of circularly spaced radial slits being formed in the body for reception of screws used in attaching the body to the water pump, and a second set of radial slits being provided in circularly spaced radially outwardly projecting ears on the body for reception of screws used in attaching the fan to the body. The opposite ends of the adapter body have circular boss portions of two different sizes for engaging and fitting closely within central apertures in fans of two different types, so that when one of the ends of the body faces forwardly it is properly positioned for mounting one type of fan, and when the other end of the body is facing forwardly the device can be used for mounting a second type of fan having a different size internal centering opening. This second discussed prior art adapter structure is in some respects even more difficult to mount than the first mentioned arrangement, being so designed that it is extremely difficult for a wrench to be brought into proper engagement with the attaching bolts to satisfactorily and quickly mount the adapter and fan.